This paper analyzes the various possible situations in which a drinking water supply in China may be contaminated by the deposition of airborne radioactive effluent after reactor accidents occur. A model was utilized to calculate the impact of ingestion of contaminated drinking water from a reservoir after a design basic accident of a 900-MWe pressurized water reactor power station. It showed that the maximum individual effective dose caused by a contaminated drinking water supply was at most 0.02% of the total individual effective dose from a reactor design basic accident. This factor was not considered when evaluating the consequence of a reactor design basic accident since, under several unfavorable conditions, the contamination of a drinking water supply from airborne radioactive effluent after a reactor design basic accident is not a major contributor to the impact on individual effective dose. It may be necessary to consider surface water contamination by deposition of airborne radioactive effluent for an emergency plan after a serious accident.